从1979年2月以来,美国线虫学家在枯死的松树木材里发现了一种线虫(Bursaphelen-chus sp),这种线虫使人联想到在日本广为传播和危害的松材线虫病。在密苏里大学的校园里首次发现这种线虫,经提取鉴定和野外调查,证明这种线虫分布于32个州,寄生于20种松树。目前,这种线虫在美国不象在日本那样严重,因为还没发现它危害本地松和在日本的 Since February 1979, American nematologist discovered a Bursaphelen-chus sp in the dead pine wood, reminiscent of the pine wilt disease widely spread and endangered in Japan. The nematode was first discovered on the University of Missouri campus and was extracted and field investigated to prove that the nematode is found in 32 states and parasitizes 20 species of pine. At present, the nematode in the United States is not as serious as in Japan because it has not been found to be harmful to native pine and in Japan